The launch power for a space shuttle craft is in the form of a pair of solid rocket boosters mounted to either side of an external tank on which the shuttle craft is supported. This arrangement along with the launch pad is transported to the launch tower where one of the solid rocket boosters, referred to as the inside booster, is located adjacent the launch tower. The other solid rocket booster referred to as the outside booster is positioned outwardly away from the tower. Both boosters are attached to the external tank and both are upright mounted at their bases directly to the launch pad.
After the system has been set-up on the launch pad and moved to the launch tower as described above, the external tank is filled with liquid oxygen in the top part of the tank and liquid hydrogen in the bottom part of the tank. These two fuels have extremely low temperatures resulting in substantial cryogenic shrinkage of the external tank. Since the inside rocket booster is supported from the tower and the outside booster is vertically unsupported other than at its base, the shrinkage results in an inward pulling on the outside booster. This can adversely affect the optimum upright positioning of the outside solid rocket booster such that it is misaligned with the inside booster.